An ingenious suprachoroidal injector based on the resistance feedback theory for treatment of macular edema: A short-term pilot study

Purpose To explore a new suprachoroidal space (SCS) injection technique using an ingenious, handmade, and precise suprachoroidal injector based on the resistance feedback theory to treat recurrent macular edema. Methods We designed a suprachoroidal injector on the basis of the resistance feedback theory and fabricated it with readily available commercial materials. Nine patients with recurrent macular edema secondary to diabetic retinopathy or retinal vein occlusion who could not afford repeated anti-vascular endothelial growth factor treatment received suprachoroidal injection of triamcinolone acetonide using this injector. Changes in SCS, macular edema and visual acuity before and after injection were evaluated. Results In all patients, anterior-segment optical coherence tomography revealed SCS expansion immediately after injection. At 1 month after injection, spectral-domain optical coherence tomography revealed a reduction in macular edema with average central subfield thickness decreasing from 574.56 ± 151.53 μm to 338.78 ± 61.26 μm, and best-corrected visual acuity improved from 0.87 ± 0.29 logMAR to 0.55 ± 0.24 logMAR. Complications such as increased intraocular pressure, cataract, retinal damage and fluid injection into the vitreous cavity were not observed. Conclusions This new injector is expected to provide an economical, safe, and precise SCS injection and may have potential for widely clinical application.